Dress in a collection of suits (4)
I believe the answer is:
deck
'dress' is the definition.
(I've seen this before)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for deck that I've seen before include "Set of cards" , "Ship's flooring; pack" , "red and black suits" , "Ship's platform" , "Pack of cards (US)" .)